The scammers are asking for payments using Western Union.
If a seller or company mentions payments using Western Union, MoneyGram they are a SCAM.
Only a sucker would follow these directions:

Royal Estate International - Payment Options: How to make payment via Money Transfer (Western Union Money Transfer)
Simply visit any Western Union Agent location. Western Union agents are located where you need them: in banks, post offices, pharmacies, retail stores, supermarkets,
railway stations, airports and other places, Most agent locations offer convenient hours and service on weekends. More than 290,000 agent locations make Western
Union the world's largest money transfer network.
Fill out a Western Union " To Send Money " form. We will send you a set of instructions on how to complete your payment to our Royal Mail Agent assigned to your
transaction.
Hand the Western Union agent your green form, your payment, plus a small transaction fee.
The agent will enter the information onto the computer.
The agent will give you a receipt with your Money Transfer Control Number (MTCN).
Once payment has been sent, simply reply to Royal Mail Customer Service or Royal Mail Payment Service and fill in the following info:
- The 10 digits Money Transfer control number (MTCN);
- Western Union Sender's Full Name;
- Exact amount and currency wired (without Western Union fee);
- Complete postal address;

The scammers even go so far as to post a bank account to throw off the intended victims:

Bank Name: The International Bank of Miami, N.A.
Address: 121 Alhambra Plaza, Coral Gables, Florida, 33134
United States Of America
ABA Routing #: 121000358
Swift Code: BOFAUS3N
Credit Account Name: Internet Royal Mail Services
Credit Account #: 01286498
That account data is fake, no such account exists and the account has been previously used for scam sites.
Why in hell would a UK based company like Royal Mail use an obscure bank account in Coral Gables?